Flaxino dark matter and stau decay

TL;DR

This paper investigates flaxino as a dark matter candidate in supersymmetric models with Peccei-Quinn symmetry breaking, focusing on stau decay and its implications for cosmology and collider detection.

Contribution

It introduces flaxino as a novel dark matter candidate arising from flatino states in supersymmetry with Peccei-Quinn symmetry breaking, analyzing its decay and detection prospects.

Findings

Stau decay to flaxino is rapid enough to preserve Big Bang Nucleosynthesis.

Flaxino can serve as a viable cold dark matter candidate.

Stau decay signatures could be observable in future collider experiments.

Abstract

If the spontaneous breaking of Peccei-Quinn symmetry comes from soft supersymmetry breaking, the fermionic partners of the symmetry-breaking fields have mass of order the gravitino mass, and are called flatinos. The lightest flatino, called here the flaxino, is a CDM candidate if it is the lightest supersymmetric particle. We here explore flaxino dark matter assuming that the lightest ordinary supersymmetric particle is the stau, with gravity-mediated supersymmetry breaking. The decay of the stau to the flaxino is fast enough not to spoil the standard predictions of Big Bang Nucleosynthesis, and its track and decay can be seen in future colliders.